First reported in 2005, bio-printers (adapted inkjet printers) were developed to try and meet the challenge of printing 3D organs, but they have had very limited success (3-17). They fabricate structures via a dropwise printing of cells with an extracellular matrix (ECM) material, which serves as the “bio-glue”. The bio-glue gels within minutes, but the cells require tens of hours to attach to the ECM. Recently, bio-printers have become commercially available (EnvisioTec, Organovo, Inc). However, success is limited to simple structures such as a single tube or an array of spheroids (17). The structures survive by passive diffusion and none even begin to approach the complexity, nor cell density of an organ. Bio-printers are also limited by slow throughput inherent in the small size/simplicity of their building materials as well as the vast number of building units that must be deposited. Bio-printers deposit (one at a time) a drop of either a spheroid (˜1,000 cells) or liquid ECM. Our single honeycomb building part has 6×106 cells, equivalent to 6,000 spheroids. Bio-printers are not creating thick structures with sufficient density of cells to require perfusion. They are creating structures of modest thickness, high ECM content and low cell density that do not require perfusion.
Current pick-and-place instruments from the electronics industry are not suitable, nor could they be easily modified since our building must always occur within an aqueous environment of cell culture medium. We also investigated microbiology instruments for picking bacterial colonies and these were deemed not suitable because they locate a colony and punch out a small plug of agarose and dispense this plug (with colony) to a 96 well plate. These instruments (e.g., Hudson Robotics) are designed for very high throughput, do not have the precision we need, would certainly damage our tissues and cannot grip, let alone perfuse a growing organ. Hence, there is no off the shelf pick and place device available which we can modify for our intended research projects.
Therefore, a new device and method are that overcome or minimize the above-referenced problems.